“He’s done a fantastic job. He provides an incredible goal-threat and is often unstoppable for opposing defenders when going forward,” Sebastian Geppert, his youth team coach at Dortmund, told Bundesliga.com.

The precocious youngster was born in Cameroon and doubts have been expressed about his age, but according to the official certificate, issued at the German consulate in Yaounde, his date of birth is November 20, 2004.

Dortmund is earning a reputation for developing young talent having sold Ousmane Dembele for 105 million euros ($125 million) last week, despite paying Rennes just 15 million euros for the 20-year-old French winger a year ago.

Before the transfer window closed on Thursday, Dortmund signed English teenager Jadon Sancho reportedly for eight million euros, after the 17-year-old winger scored 20 goals for Manchester City’s Under-18 team.